<div class="tooltip">
  Hover me
  <div class="tooltiptext">Hi there !</div>
</div>

<style>
/* From Uiverse.io by G4b413l  - Tags: tooltip, button, button hover effect  */
.tooltip {
  position: relative;
  display: inline-block;
  cursor: pointer;
  background-color: #282828;
  color: #f1f1f1;
  padding: 1em 3em;
  border-radius: 1em;
}

.tooltip .tooltiptext {
  visibility: hidden;
  width: 200px;
  background-color: #28282817;
  color: #282828;
  text-align: center;
  border-radius: 5px;
  padding: 10px;
  position: absolute;
  z-index: 1;
  bottom: 125%;
  left: 50%;
  transform: translateX(-50%);
  opacity: 0;
  transition: opacity 0.3s;
}

.tooltip:hover .tooltiptext {
  visibility: visible;
  opacity: 1;
}

.tooltip .tooltiptext::after {
  content: "";
  position: absolute;
  top: 100%;
  left: 50%;
  border-width: 8px;
  border-style: solid;
  border-color: #28282817 transparent transparent transparent;
  transform: translateX(-50%);
}

</style>
    